drm/xe: Fix a NULL vs IS_ERR() bug in xe_i2c_register_adapter()

The fwnode_create_software_node() function returns error pointers. It
never returns NULL. Update the checks to match.

Fixes: f0e53aadd702 ("drm/xe: Support for I2C attached MCUs")
Signed-off-by: Dan Carpenter <[e-mail]>
Reviewed-by: Rodrigo Vivi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rodrigo Vivi <[e-mail]>
(cherry picked from commit 2f264d58cc805a3cefc6b98097f90fbc388136ef)
Signed-off-by: Rodrigo Vivi <[e-mail]>

drivers/gpu/drm/xe/xe_i2c.c

···
 	int ret;
 
 	fwnode = fwnode_create_software_node(xe_i2c_adapter_properties, NULL);
-	if (!fwnode)
-		return -ENOMEM;
+	if (IS_ERR(fwnode))
+		return PTR_ERR(fwnode);
 
 	/*
 	 * Not using platform_device_register_full() here because we don't have